NCCN Guidelines for Patients® | Colon Cancer - page 10

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NCCN Guidelines for Patients™: Colon Cancer
Version 1.2012
2.2 What is colon cancer?
Cells are the building blocks that form tissue in the body.
Normal cells grow and then divide to form new cells. New
cells are formed as the body needs them. When normal
cells grow old or get damaged, they die. Cancer cells
do not do this. Cancer cells make new cells that aren’t
needed and don’t die when old or damaged (Figure 4).
Over time, cancer cells grow and divide enough to
form a tumor.
Unlike normal cells, cancer cells can spread to other
parts of the body. This process is called metastasis. The
uncontrolled growth and spread of cancer cells makes
cancer dangerous. Cancer cells can replace or deform
normal tissue causing vital organs to stop working.
Colon cancer often starts in a polyp. A polyp is an extra
growth of tissue from the epithelium of the colon wall
(Figure 5). Cancer that starts in epithelial cells is called
adenocarcinoma. Not all polyps are likely to become
cancerous. For more information on polyps, see Part 2.3.
Polyps can be removed before any cancer cells form. If
you have a polyp with cancer, you can likely be cured if
the cancer hasn’t spread far. When polyps aren’t treated,
the cancer can grow through the colon wall and spread
through the body. A cure may be impossible when colon
cancer has metastasized.
Part 2: About colon cancer
Figure 4.
Normal versus cancer cell growth
Illustration Copyright © 2011 Nucleus Medical Media, All rights reserved.
Figure 5.
Start of colon cancer
Illustration Copyright © 2011 Nucleus Medical Media, All rights reserved.
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